Rose of Sharon
This article is part of a weekly series published in the Batavia Daily News by Jan Beglinger, Agriculture Outreach Coordinator for CCE of Genesee County.
Master Gardener Corner: Rose of Sharon Originally Published: Week of August 23, 2016 Rose of Sharon (Hibiscus syriacus), sometimes called “shrub Althea”, is an old fashioned favorite. It is still popular with gardeners because it blooms in late summer , when few other shrubs are in flower. Native to China and India, this deciduous flowering shrub is hardy in zones 5 to 8. The main reason we grow Rose of Sharon is for the flowers. Purple, lavender, red, pink, white and blue flowers or combinations of these colors give our summer gardens a tropical flare. Blooms resemble hollyhock flowers and they may be single or double. When in bloom the plants are loaded with five-petaled flowers that can be three to five inches in diameter. Individual flowers last for three days but the plants generally bloom from mid-summer into fall. After flowering, brown woody seed pods form. Rose of Sharon can be prolific creating numerous seedlings under the right conditions. The best flowering occurs when plants are grown in full sun. A common problem with some plants are bud drop or plants failing to bloom at all. No one really seems to know why they do this. Plants flower on new growth so it should still produce buds even after a rough winter. Sometimes the plant will have many buds but they don’t open or they start out blooming normally but then later in the season the remaining buds drop. One reason is that the plants could be stressed by environmental conditions, such as not enough moisture. Rose of Sharon are considered to be relatively easy to grow and low maintenance. They prefer moist, organically rich soils but will tolerate a wide range of conditions. They do not like extremely wet or dry soils. Once established they are considered drought tolerant. Plants are also tolerant of our hot and humid summer weather. New plants can be grown from seed but your resulting plants may not have the same color flower as the parent. Ripened seeds are easy to collect. Pick the pods as they start to open and shake the seeds into a paper bag or envelope. If you want your new plant to be the identical to the parent plant you can take stem cuttings to propagate it. Rose of Sharon can be propagated using either softwood (spring/early summer) or hardwood (dormant) cuttings. Typically Rose of Sharon plants will grow ten to fifteen feet tall with a spread of six to ten feet. These are large shrubs that need space. As they grow, they develop a vase-shaped form. They may become leggy at the base. In the landscape this open habit probably looks best at the back of a border. Rose of Sharon shrubs look good when planted in groups, or used as an informal hedge or summer-flowering shrub border. Because of their height they can screen out an unwanted view. They should be spaced six to eight feet apart when used as a hedge or screen.
If you grow Rose of Sharon, you may have noticed that it leafs out later than many shrubs. Sometimes you wonder if it survived the winter. The glossy dark green leaves are serrated and triangular in shape. There is not much of a fall display as leaves remain green through late autumn. They may turn a yellow-green. Rose of Sharon should be pruned in late winter or early spring (if needed) as it blooms on the current season’s new growth. When given enough room to grow, it does not need any regular pruning. If it has gotten too tall it can be pruned back hard to keep the plant more compact. Consider its mature size when planting or you may be chopping it back annually. Winter killed stems and any dead or diseased wood should be pruned out. You can prune to shape in spring. Japanese beetles are a problem in some years and can damage leaves and blooms. They can also damage buds to the point where they will not open. Thrips are another insect pest that feed on flower buds and can cause bud drop. Botrytis (a fungal disease) can infect flower buds and cause them to turn brown and drop off before opening. On the plus side, Rose of Sharon are said to be deer resistant and the big colorful blooms will attract bees, butterflies and hummingbirds. Dozens of varieties are now available. The Chiffon series are newer cultivars with an unusual flower shape described as anemone-like. The single blooms have five big petals but the center of the flower is almost double, frequently described as lacy. They are available in white, pink, blue and lavender flowers. There is even one variety called ‘China Chiffon’ which has large white flowers with an attractive red eye peeking out of the center. ‘Azurri Blue Satin’ has huge, rich purple-blue blossoms with magenta and white centers. This was the first seedless Rose of Sharon. ‘Sugar Tip’ has variegated creamy-white and bluish-green foliage which is attractive all season. The soft pink double blooms do not produce seed. For those who don’t have room for a full size shrub, try ‘Lil' Kim.’ Growing only 3 to 5 feet tall and 2 to 4 feet wide, the three inch white flowers have a showy magenta center eye. If you like purple flowers look for ‘Lil' Kim Violet.’ New this year is ‘Lil' Kim Red’, which has deep rosy-red flowers and a red center eye. Both are compact in size. ‘Azurri Blue Satin’ Photo source: Proven Winners
If you want late season color, blooming Rose of Sharon can give your garden a tropical feel and a burst of bright color.
Resources for this article include: Missouri Botanical Garden, Purdue University, Colorado State University, University of Connecticut and Proven Winners.
Master Gardener Corner: Rose of Sharon Originally Published: Week of August 23, 2016 Rose of Sharon (Hibiscus syriacus), sometimes called “shrub Althea”, is an old fashioned favorite. It is still popular with gardeners because it blooms in late summer , when few other shrubs are in flower. Native to China and India, this deciduous flowering shrub is hardy in zones 5 to 8. The main reason we grow Rose of Sharon is for the flowers. Purple, lavender, red, pink, white and blue flowers or combinations of these colors give our summer gardens a tropical flare. Blooms resemble hollyhock flowers and they may be single or double. When in bloom the plants are loaded with five-petaled flowers that can be three to five inches in diameter. Individual flowers last for three days but the plants generally bloom from mid-summer into fall. After flowering, brown woody seed pods form. Rose of Sharon can be prolific creating numerous seedlings under the right conditions. The best flowering occurs when plants are grown in full sun. A common problem with some plants are bud drop or plants failing to bloom at all. No one really seems to know why they do this. Plants flower on new growth so it should still produce buds even after a rough winter. Sometimes the plant will have many buds but they don’t open or they start out blooming normally but then later in the season the remaining buds drop. One reason is that the plants could be stressed by environmental conditions, such as not enough moisture. Rose of Sharon are considered to be relatively easy to grow and low maintenance. They prefer moist, organically rich soils but will tolerate a wide range of conditions. They do not like extremely wet or dry soils. Once established they are considered drought tolerant. Plants are also tolerant of our hot and humid summer weather. New plants can be grown from seed but your resulting plants may not have the same color flower as the parent. Ripened seeds are easy to collect. Pick the pods as they start to open and shake the seeds into a paper bag or envelope. If you want your new plant to be the identical to the parent plant you can take stem cuttings to propagate it. Rose of Sharon can be propagated using either softwood (spring/early summer) or hardwood (dormant) cuttings. Typically Rose of Sharon plants will grow ten to fifteen feet tall with a spread of six to ten feet. These are large shrubs that need space. As they grow, they develop a vase-shaped form. They may become leggy at the base. In the landscape this open habit probably looks best at the back of a border. Rose of Sharon shrubs look good when planted in groups, or used as an informal hedge or summer-flowering shrub border. Because of their height they can screen out an unwanted view. They should be spaced six to eight feet apart when used as a hedge or screen.
If you grow Rose of Sharon, you may have noticed that it leafs out later than many shrubs. Sometimes you wonder if it survived the winter. The glossy dark green leaves are serrated and triangular in shape. There is not much of a fall display as leaves remain green through late autumn. They may turn a yellow-green. Rose of Sharon should be pruned in late winter or early spring (if needed) as it blooms on the current season’s new growth. When given enough room to grow, it does not need any regular pruning. If it has gotten too tall it can be pruned back hard to keep the plant more compact. Consider its mature size when planting or you may be chopping it back annually. Winter killed stems and any dead or diseased wood should be pruned out. You can prune to shape in spring. Japanese beetles are a problem in some years and can damage leaves and blooms. They can also damage buds to the point where they will not open. Thrips are another insect pest that feed on flower buds and can cause bud drop. Botrytis (a fungal disease) can infect flower buds and cause them to turn brown and drop off before opening. On the plus side, Rose of Sharon are said to be deer resistant and the big colorful blooms will attract bees, butterflies and hummingbirds. Dozens of varieties are now available. The Chiffon series are newer cultivars with an unusual flower shape described as anemone-like. The single blooms have five big petals but the center of the flower is almost double, frequently described as lacy. They are available in white, pink, blue and lavender flowers. There is even one variety called ‘China Chiffon’ which has large white flowers with an attractive red eye peeking out of the center. ‘Azurri Blue Satin’ has huge, rich purple-blue blossoms with magenta and white centers. This was the first seedless Rose of Sharon. ‘Sugar Tip’ has variegated creamy-white and bluish-green foliage which is attractive all season. The soft pink double blooms do not produce seed. For those who don’t have room for a full size shrub, try ‘Lil' Kim.’ Growing only 3 to 5 feet tall and 2 to 4 feet wide, the three inch white flowers have a showy magenta center eye. If you like purple flowers look for ‘Lil' Kim Violet.’ New this year is ‘Lil' Kim Red’, which has deep rosy-red flowers and a red center eye. Both are compact in size. ‘Azurri Blue Satin’ Photo source: Proven Winners
If you want late season color, blooming Rose of Sharon can give your garden a tropical feel and a burst of bright color.
Resources for this article include: Missouri Botanical Garden, Purdue University, Colorado State University, University of Connecticut and Proven Winners.
